Touch display device comprising a plurality of first and second common electrodes wherein the first common electrode includes first and second slits

ABSTRACT

According to one embodiment, a display device comprises image signal lines, scanning signal lines, pixels, a display area, pixel electrodes, and common electrodes. The common electrodes are configured to detect an object and to display an image in the display area. The common electrodes include first and second common electrodes which are arranged in a first direction. A first slit is provided between the first and second common electrodes. The first and second common electrodes are supplied a signal different from each other. A second slit is provided in the first common electrode. Each of the first slit and the second slit overlaps one of the image signal lines and extends in an extension direction in which the image signal line extends.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2016-033222, filed Feb. 24, 2016, theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a display device.

BACKGROUND

Recently, a display device which causes a common electrode which isarranged in a display area to function as a display electrode whichproduces an electric filed between the display electrode and a pixelelectrode and also function as a detection electrode which detects anobject which is in contact with or in proximity to the display area hasbeen developed.

For example, a liquid crystal display device including a plurality ofcommon electrodes which extend in an extension direction of scanningsignal lines (gate lines), are arranged in an extension direction ofimage signal lines (source lines), and are used as object detectionelectrodes has been known. In the liquid crystal display device, slitswhich extend in the extension direction of the scanning signal lines areformed between the common electrodes. Between areas in which the slitsare provided and areas in which the slits are not provided, thealignment of liquid crystal molecules may differ. Therefore, it isconsidered that, as slits are further provided in each of the commonelectrodes, the impact of the slits can be averaged across the displayarea.

In realizing common electrodes which function as detection electrodes,if the common electrodes are arranged such that the common electrodesextend in the extension direction of the image signal lines and arearranged in the extension direction of the scanning signal lines, theframe size can be reduced. In this structure, the slit between theadjacent common electrodes extends along the image signal, and thus theelectric field from the image signal line may leak through the slit andmay have an impact on the display performance. Therefore, even in adisplay device of this kind, it is still necessary to take some measuresto improve display quality.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically showing the structure of a displaydevice of a first embodiment.

FIG. 2 is a diagram showing an equivalent circuit related to imagedisplay of the display device.

FIG. 3 is a plan view schematically showing an example of the structureapplicable to a subpixel.

FIG. 4 is a sectional diagram taken along line IV-IV of FIG. 3.

FIG. 5 is a plan view schematically showing the shapes of a plurality ofcommon electrodes.

FIG. 6 is a diagram showing the detailed structures of the commonelectrodes.

FIG. 7 is an explanatory diagram showing the impact of a slit betweenthe common electrodes.

FIG. 8 is a graph showing the result of an experiment on a streak due tothe slit.

FIG. 9 is a graph showing the relationship between the performance ofthe display device and the number of pixels between the slits.

FIG. 10 is a plan view showing an example of the layout of metal linesand the common electrodes.

FIG. 11 is a plan view schematically showing the structure of a secondembodiment.

FIG. 12 is a plan view schematically showing the structure of a thirdembodiment.

FIG. 13 is a plan view schematically showing the structure of a fourthembodiment.

FIG. 14 is a sectional diagram taken along line XIV-XIV of FIG. 13.

DETAILED DESCRIPTION

In general, according to one embodiment, a display device comprises aplurality of image signal lines, a plurality of scanning signal linescrossing the plurality of image signal lines, a plurality of pixels, adisplay area including the plurality of pixels, a plurality of pixelelectrodes which are respectively provided in the plurality of pixels,and a plurality of common electrodes which are respectively opposed tothe plurality of pixel electrodes. The plurality of common electrodesare configured to detect an object which is in contact with or inproximity to the display area and to display an image in the displayarea. The plurality of common electrodes include a first commonelectrode and a second common electrode which are arranged in a firstdirection in which one of the plurality of scanning signal linesextends. A first slit is provided between the first common electrode andthe second common electrode. The first common electrode and the secondcommon electrode are supplied a signal different from each other. Asecond slit is provided in the first common electrode. Each of the firstslit and the second slit overlaps one of the image signal lines andextends in an extension direction in which the image signal lineextends.

Embodiments will be described hereinafter with reference to theaccompanying drawings.

The disclosure is merely an example, and proper changes in keeping withthe spirit of the invention, which are easily conceivable by a person ofordinary skill in the art, come within the scope of the invention as amatter of course. In addition, in some cases, in order to make thedescription clearer, the respective parts are illustrated in thedrawings schematically, rather than as an accurate representation ofwhat is implemented. However, such schematic illustration is merelyexemplary and in no way restricts the interpretation of the invention.In the drawings, reference numbers of continuously arranged elementsequivalent or similar to each other are omitted in some cases. Inaddition, in the specification and drawings, structural elementsequivalent or similar to those described in connection with precedingdrawings are denoted by the same reference numbers, and detaileddescription thereof is omitted unless necessary.

In each embodiment, an example of the display device, a liquid crystaldisplay device which performs a touch detection function will bedescribed. However, the embodiment does not preclude the application ofan individual technical idea disclosed in the embodiment to variousother display devices. As the display device other than the liquidcrystal display device, a self-luminous display device such as anorganic electroluminescent display device, an electronic-paper typedisplay device comprising an electrophoresis element or the like may beconsidered.

First Embodiment

FIG. 1 is a diagram schematically showing the structure of a displaydevice 1 of the first embodiment. The display device 1 includes adisplay panel 2, a plurality of common electrodes CE, a plurality ofdetection electrodes RX which are respectively opposed to the commonelectrodes CE, a driver IC 3 which controls image display, and a touchdetection IC 4 which controls touch detection.

The display panel 2 includes an array substrate AR (first substrate), acountersubstrate CT (second substrate) which is smaller in outer shapethan the array substrate AR, and a liquid crystal layer (liquid crystallayer LC which will be described later) which is provided between thesesubstrates AR and CT. In an area where these substrates AR and CT areopposed to each other, the display panel 2 includes a display area DAwhich displays an image, and a surrounding area SA outside the displayarea DA. Further, the array substrate AR includes a terminal area NAwhich is not opposed to the countersubstrate CT.

In the display area DA, the detection electrodes RX extend in a firstdirection D1 and are arranged in a second direction D2. In the displayarea DA, the common electrodes CE extend in the second direction D2 andare arranged in the first direction D1. In the present embodiment, thesedirections D1 and D2 are orthogonal to each other. Note that thesedirections D1 and D2 may also cross each at various other angles.

The driver IC 3 is provided, for example, in the terminal area NA. Tothe terminal area NA, a first flexible printed circuit board 6 whichsupplies image data to the display panel 2 is connected via a mountingterminal 5. To the end of the countersubstrate CT, a second flexibleprinted circuit board 8 which outputs detection signals from thedetection electrodes RX is connected via a mounting terminal 7. Thedetection electrodes RX are connected to the mounting terminal 7 viadetection lines DL which are formed in the surrounding area SA, forexample.

FIG. 2 is a schematic diagram showing the equivalent circuit related tothe image display of the display device 1. The display device 1 includesa first driver DR1, a second driver DR2, a plurality of scanning signallines G which are connected to the first driver DR1, and a plurality ofimage signal lines S which are connected to the second driver DR2. Inthe display area DA, the scanning signal lines G extend in the firstdirection D1 and are arranged in the second direction D2. In the displayarea DA, the image signal lines S extend in the second direction D2 andare arranged in the first direction D1, and cross the scanning signallines G, respectively.

Areas which are defined by the scanning signal lines G and the imagesignal lines S correspond to subpixels SP, respectively. In the presentembodiment, one pixel PX includes a subpixel SPR which performs reddisplay, a subpixel SPG which performs green display, and a subpixel SPBwhich performs blue display. Note that the pixel PX may also include asubpixel SP which performs white display or the pixel PX may alsoinclude a plurality of subpixels SP which correspond to the same color.

Each of the subpixels SP includes a switching element SW and a pixelelectrode PE which is opposed to the common electrode CE. The switchingelement SW is electrically connected to the scanning signal line G, theimage signal line S, and the pixel electrode PE. The first driver DR1supplies a scanning signal to the scanning signal lines G, and thesecond driver DR2 supplies an image signal to the image signal lines S.As an electric filed which is produced between the pixel electrode PEand the common electrode CE acts on the liquid crystal layer LC, animage is displayed in the display area DA.

The common electrode CE functions not only as a display electrode butalso as a detection electrode which detects an object (conductor) suchas a user's finger which is in contact with or in proximity to thedisplay area DA. In the detection operation, the driver IC 3sequentially supplies a drive signal to the common electrodes CE. Eachof the detection electrodes RX is capacitively coupled with each of thecommon electrodes CE. According to the drive signal which is supplied toeach of the common electrodes CE, each of the detection electrodes RXoutputs a detection signal. Based on the detection signal, the touchdetection IC 4 detects an object which is in contact with or inproximity to the display area DA. Note that the detection method isdescribed by way of example only and various other detection methods arealso applicable. For example, an object detection method using acapacitance (self capacitance) of the detection electrode RX or thecommon electrode CE is also applicable.

FIG. 3 is a plan view schematically showing an example of the structurewhich is applicable to the subpixel SP. The subpixel SP is defined bythe two adjacent scanning signal lines G and the two adjacent imagesignal lines S. In this example, the image signal lines S windinglyextend in the second direction D2. The subpixel SP includes two branchesBP which are elongated in the extension direction of the image signalline S. The pixel electrode PE does not necessarily have theabove-described shape and may have more branches BP. The commonelectrode CE is opposed to the pixel electrode PE.

A metal line ML is provided at the boundary of the adjacent subpixels SPwhich are arranged in the first direction D1. The metal lines ML areopposed to the image signal lines S and extend in the extensiondirection of the image signal lines S. In the example shown in FIG. 3,the metal lines ML completely overlap the image signal lines S in planarview. However, the metal lines ML and the image signal lines S maypartly overlap each other in planar view.

At the boundaries of the subpixels SP, a light-blocking layer BM isformed. In FIG. 3, dashed-dotted lines show the outline of thelight-blocking layer BM. In planar view, the light-blocking layer BMoverlaps the scanning signal lines G, the image signal lines S, and themetal lines ML, and opens in the subpixels SP.

FIG. 4 is a sectional diagram taken along line IV-IV of FIG. 3. Thearray substrate AR includes a first insulating substrate 10, a firstinsulating layer 11, a second insulating layer 12, a third insulatinglayer 13, a first alignment film 14, the image signal lines S, the pixelelectrodes PE, and the common electrodes CE.

The first insulating layer 11 entirely covers the first insulatingsubstrate 10. The image signal lines S are formed on the firstinsulating layer 11. The second insulating layer 12 covers the firstinsulating layer 11 and the image signal lines S. The common electrodesCE are formed on the second insulating layer 12. The metal lines ML areformed on the common electrode CE. The third insulating layer 13 coversthe metal lines ML and the common electrodes CE. The pixel electrodes PEare formed on the third insulating layer 13. The first alignment film 14covers the pixel electrodes PE and the third insulating layer 13. Thepixel electrodes PE and the common electrodes CE are formed of atransparent conductive material such as indium tin oxide (ITO).

The countersubstrate CT includes a second insulating substrate 20, acolor filter 21, a flattening layer 22, and a second alignment film 23,and the light-blocking layer BM. The light-blocking layer BM and thecolor filter 21 are formed across the entire second insulating substrate20. The flattening layer 22 covers the color filter 21. The secondalignment film 23 covers the flattening layer 22.

The liquid crystal layer LC is sealed between the first alignment film14 and the second alignment film 23. The detection electrodes RX areformed, for example, on the outer surface of the second insulatingsubstrate 20.

As shown in FIG. 4, the metal lines ML and the common electrodes CE arein contact with each other. In this way, the metal lines ML and thecommon electrode CE are electrically connected to each other. Note thatthe metal lines ML may also be formed between the second insulatinglayer 12 and the common electrodes CE.

Here, the structure of the common electrode CE will be described indetail. FIG. 5 is a plan view schematically showing the plurality ofcommon electrodes CE which are arranged in the second direction D2. Afirst slit SL1 is formed between the adjacent common electrodes CE.Further, a plurality of second slits SL2 (dummy slits) are formed ineach of the common electrodes CE. These slits SL1 and SL2 extend in thesecond direction D2 (in the extension direction of the image signallines S) and overlap the image signal lines S in planar view.

The first slit SL1 physically separates one common electrode CE fromanother common electrode CE. That is, the adjacent common electrodes CEare electrically separated from each other by the first slit SL1 andsupplied a signal different from each other. On the other hand, thesecond slits SL2 do not completely split the common electrode CE intopieces. That is, a part of the common electrode CE on the right side ofthe second slit SL2 and a part of the common electrode CE on the leftside of the second slit LS2 are electrically connected to each other.Note that, when components are electrically separated, the componentscan supply different potentials.

The first slit SL1 has a width W1 in the first direction D1, and thesecond slit SL2 has a width W2 in the first direction D1. The width W1and the width W2 are, for example, the same as each other. Note that,since the common electrodes CE which are adjacent to each other via thefirst slit SL2 must be electrically insulated from each other, the widthW1 may be set to be greater than the width W2 (W1>W2).

These slits SL1 and SL2 are arranged in the first direction D1 with apitch P. That is, the distance between the first slit SL1 and the secondslit SL2 which is adjacent to the first slit SL1 is the same as thedistance between the adjacent second slits SL2.

FIG. 6 is a diagram showing the more detailed structure of the commonelectrode CE. In the drawing, one first slit SL1 and one second slit SL2are illustrated. For example, as in the case of the image signal lines Sshown in FIG. 3, these slits SL1 and SL2 windingly extend in the seconddirection D2.

In the display area DA, the pixels PX are arranged between these slitsSL1 and SL2. In the example shown in FIG. 6, in the pixel PX, thesubpixels SPR (R), SPG (G) and SPB (B) are arranged in the firstdirection D1.

These slits SL1 and SL2 are formed at the boundaries of the adjacentpixels PX which are arranged side by side in the first direction D1.Therefore, in the example shown in FIG. 6, each of the slits SL1 and SL2extends at the boundary between the subpixel SPR and the subpixel SPB.Note that each of the slits SL1 and SL2 may extend at the boundarybetween the subpixels SP which correspond to other colors.

The common electrode CE includes a first area A1, a second area A2 whichis adjacent to the first area A1, and a third area A3 which is adjacentto the second are A2. These areas A1 to A3 are arranged in the seconddirection D2. The first area A1 is located on the upper side of thesurrounding area A1 (the side opposite to the terminal area NA side) inthe drawing. The third area A3 is located on the lower side of thesurrounding area SA (the terminal area NA side) in the drawing. Thesecond area A2 is located in the display area DA. In the example shownin FIG. 6, the second area A2 partly extends over the upper part of thesurrounding area SA and the lower part of the surrounding area SA.

In the first area A1 and the third area A3, the second slit SL2 is notformed. On the other hand, the second slit SL2 is formed in the secondarea A2. In this structure, the common electrodes CE which are adjacentto each other via the second slit SL2 are partly connected to each otherin the upper part of the surrounding area SA and the lower part of thesurrounding area SA.

The above-described light-blocking layer BM is also formed in thesurrounding area SA. In FIG. 6, the dashed-dotted lines show the edgesof the light-blocking layer BM which is formed in the surrounding areaSA. In the drawing, the light-blocking layer BM which is formed in thedisplay area DA is omitted. The first area A1 and the third area A3overlap the light-blocking layer BM in planar view.

Note that the common electrodes CE which are adjacent to each other viathe second slit SL2 are not necessarily connected to each other in theabove-described manner. For example, these common electrodes CE may bepartly connected to each other only in either of the upper part of thesurrounding area SA and the lower part of the surrounding area SA or maybe partly connected to each other, for example, in positions where thecommon electrodes CE overlap the scanning signal lines G in the displayarea DA.

Here, the impact of the first slit SL1 on the display quality will bedescribed with reference to FIG. 7. In the drawing, the planar shape ofthe display panel 2 is illustrated. It is assumed that, for example, awhite image and a surrounding, that is, a rectangular high-luminancearea HA and a low-luminance area LA are displayed in the display areaDA.

As described above, the first slit SL1 overlaps the image signal line Sin planar view. Therefore, an electric field is produced between theimage signal line S and the pixel electrode PE via the first slit SL1,and the electric field acts on the liquid crystal layer LC. As a result,an undesirable streak may be visually recognized along the first slitSL1.

In the first slit SL1 which overlaps the image signal line S (which isassumed to be an image signal line of a blue subpixel in the presentembodiment) which crosses the high-luminance area HA, the streak becomesnoticeable. In the example shown in FIG. 7, steaks L1 which are createdin an area MA1 below the high-luminance area HA, and streaks L2 whichare created in an area MA2 above the high-luminance area HA (on theopposite side to the terminal area NA side) are illustrated. The colorof light which leaks from these streaks L1 and L2 will be the halftoneof the colors (red and blue in the present embodiment) of the subpixelsSP which are adjacent to each other via the first slit SL1. Further,since a voltage which is applied to the image signal line S decreaseswith distance from the terminal area NA, an amount of the electric fieldwhich leaks from the image signal line S in the streak L2 is less thanan amount of the electric field which leaks from the image signal line Sin the streak L1. In this case, for example, when the low-luminance areaLA is blue, the streak L1 becomes a high-intensity, bright line underthe influence of the leakage of the electric field in the image signalline of the blue subpixel, and the streak L2, which is less influencedby the leakage of the electric field, becomes a lower-intensity, darkerline than the line of the streak L1. Further, if the low-luminance areaLA is red, the streak L1 becomes a dark line under the influence of theleakage of the electric field in the image signal line of the bluesubpixel on the red display, and the streak L2, which is less influencedby the leakage of the electric field, becomes a brighter line than theline of the streak L1.

In the present embodiment, the second slits SL2 are provided between thefirst slits SL1. In this case, similar streaks are also created by thesecond slits SL2. Note that, as compared to a case where the secondslits SL2 are not provided, the streaks created by these slits SL1 andSL2 are arranged with a smaller pitch (at a higher frequency). When thepitch is sufficiently small, each individual streak cannot be recognizedby the viewer, and thus the impact on the image quality can be reduced.

The inventors have conducted an experiment and examined the relationshipbetween the pitch P of these slits SL1 and S12 and the visibility of thestreaks. FIG. 8 is a graph showing the results of the experiment. In theexperiment, the pitch P was changed in several ways, and the streakscreated at the respective pitches P were presented to viewers. In thegraph, the horizontal axis shows the pitch P [μm], and the vertical axisshows the percentage of the viewers who could recognize the streaks (thevisibility).

At a large pitch P of 2000 μm, the visibility was substantially 100%.Further, as the pitch P became smaller, the visibility decreased, andthe visibility was significantly low at a pitch P of about 180 μm, andthe visibility was 0% at a pitch P of 150 μm or less. As is evident fromthe results, each individual streak will become sufficiently invisiblewhen the pitch P is less than or equal to 180 μm, more preferably, whenthe pitch P is 150 μm.

Note that, if the pitch P is too small, each individual streak will notbe visually recognized, but the number of subpixels under the influenceof the leakage of electric fields increases. As a result, the displaycolor in the areas MA1 and MA2 shown in FIG. 7 may become different fromthe target display color. To prevent this phenomenon, the pitch P shouldpreferably be as large as possible under the condition that the pitch Pis less than or equal to 180 μm or less than or equal to 150 μm. Forexample, the pitch P should be greater than or equal to 80 μm. Moredesirably, the pitch P should be greater than or equal to 100 μm.

These slits SL1 and SL2 should preferably be formed the boundaries ofthe pixels PX. In this case, there is unity of color among the subpixelsSP which are adjacent to each other via these slits SL1 and SL2, andthus the colors of the streaks becomes similar to each other. Therefore,when the frequency of the pitch P is increased, the visibility of thestreaks can be easily decreased. Further, it is preferable that theimage signal lines S which overlap these slits SL1 and SL2 are the imagesignal lines S which correspond to the same color. For example, both ofthe image signal lines S should preferably be image signal lines S ofblue subpixels.

When these slits SL1 and SL2 are formed at the boundaries of the pixelsPX, the pitch P is limited by the size of the pixel PX. FIG. 9 is agraph showing the relationship between the pixels per inch (ppi) of thedisplay device 1 and the number (m) of the pixels PX which are arrangedbetween these slits SL1 and SL2 or between the adjacent slits SL2. Here,the pitch P is set to be as large as possible within the range of lessthan or equal to 150 μm. As shown in the graph, m=1 in the case of adisplay device of about 350 ppi or less, and m=4 in the case of ahigh-definition display device of about 650 ppi or more. Further, whenthe pixels per inch is in between, the number of the pixels PX betweenthe adjacent slits is set to three and then to four step by step (m=3,4).

Here, the number of the subpixels SP which are included in the pixel PXis defined as n. In the case of forming the slits SL1 and SL2 at theboundaries of the pixels PX, the number of the subpixels SP which arearranged between the adjacent slits SL1 and SL2 and between the twoadjacent second slits SL2 in the first direction D1 will be an integralmultiple of n. In the present embodiment, n=3.

In the first direction D1, depending on the relationship between thenumber (q) of the pixels PX which overlap one common electrode CE andthe number (m) of the pixels PX between the adjacent slits, the pitch Pwill not be constant. For example, when m=3 and if q=43, in at least oneportion, the number of the pixels PX between the adjacent slits needs tobe adjusted to two or four. In this case, the pitch P will not beperiodic, and the streak corresponding to the adjustment will bevisually recognized. Therefore, the common electrode CE shouldpreferably have such a shape, etc., that the number (q) of the pixels PXwhich overlaps one common electrode CE will be an integral multiple ofthe number (m) of the pixels PX between the adjacent slits. In thiscase, the pixel P becomes constant.

The number (q) of the overlapping pixels PX may differ from one commonelectrode CE to another common electrode CE. In this case also, thenumber (q) of the overlapping pixels PX in each common electrode CEshould be an integral multiple of the number (m) of the pixels PXbetween the adjacent slits. For example, when m=3, if the number (q1) ofthe pixels PX which overlap one common electrode CE is set to 42 and thenumber (q2) of the pixels PX which overlap the next common electrode CEis set to 45, the pitch P will be constant across these commonelectrodes CE.

Subsequently, the relationship between the metal line ML and the commonelectrode CE will be described. FIG. 10 is a plan view schematicallyshowing an example of the layout of the metal lines ML and the commonelectrodes CE. Here, two common electrodes CE and metal lines ML nearthree successively-arranged scanning signal lines G are partlyillustrated. These two common electrodes CE are hereinafter referred toas a first common electrode CE1 and a second common electrode CE 2.

The metal lines ML are provided not only in positions where the slitsSL1 and SL2 are not formed but also in positions where the slits SL1 andSL2 are formed. The metal line ML corresponding to the first slit SL1which is provided between the common electrodes CE1 and CE2 ishereinafter referred to as a first metal line ML1, and the metal line MLcorresponding to the second slit SL2 which is provided in the firstcommon electrode CE1 is hereinafter referred to as a second metal lineML2.

The common electrode CE is composed of a plurality of structuralelectrodes SE. The structural electrode SE corresponds to an area whichis defined by the two adjacent scanning signal lines G and the twoadjacent slits (SL1 and SL2, or SL2 and SL2). In FIG. 10, six structuralelectrodes SE are illustrated. These structural electrodes SE arehereinafter referred to as a first structural electrode SE1 to a sixstructural electrode SE6.

The structural electrodes SE1, SE2, SE4 and SE5 are included in thefirst common electrode CE1, and the structural electrodes SE3 and SE6are included in the second common electrode CE2. The first structuralelectrode SE1 and the second structural electrode SE2 are adjacent toeach other via the second slit SL2. The second structural electrode SE2and the third structural electrode SE3 are adjacent to each other viathe first slit SL1. The fourth structural electrode SE4 and the fifthstructural electrode SE5 are adjacent to each other via the second slitSL2. The fifth structural electrode SE5 and the sixth structuralelectrode SE6 are adjacent to each other via the first slit SL1. Thefirst structural electrode SE1 and the fourth structural electrode SE4,the second structural electrode SE2 and the fifth structural electrodeSE5, and the third structural electrode SE3 and the sixth structuralelectrode SE6 are respectively adjacent to each other in the seconddirection D2.

The first metal line ML1 partly covers the first slit SL1. The firstmetal line ML1 is in contact with the edges of the structural electrodesSE3 and SE6 and is spaced apart from the structural electrodes SE2 andSE5.

The second metal line ML2 partly covers the second slit SL2. The secondmetal line ML2 is in contact with the edges of the structural electrodesSE1 and SE4 and is spaced apart from the structural electrodes SE2 andSE5.

For example, the width of the first metal line ML1 which overlaps thefirst slit SL1 is greater than the width of the first metal line ML1which overlaps the structural electrodes SE3 and SE6. The same alsoapplies to the relationship of the second metal line ML2 to the secondslit SL2 and to the structural electrodes SE1 and SE4. To prevent ashort circuit in the common electrodes CE1 and CE2, the width of thefirst metal line ML1 may be slightly less than the width of the secondmetal line ML2 or the width of the other metal lines ML.

In the example shown in FIG. 10, subpixels on the left of the slits SL1and SL2 are the subpixels SPB, and subpixels on the right of the slitsSL1 and SL2 are the subpixels SPR. In the present embodiment, slitswhere the metal lines ML contact the edges of the structural electrodesSE on the subpixel SPB side and slits where the metal lines ML contactthe edges of the structural electrodes SE on the subpixel SPR side arealternately arranged in the first direction D1.

Note that, although FIG. 10 only shows the layout of the metal lines MLand the common electrodes CE between the three scanning signal lines G,the metal lines ML are arranged in the same manner, for example,throughout the entire length of the metal lines ML.

If the metal lines ML are not arranged in the slits SL1 and SL2,depending on view angles with respect to the display area DA, thedisplay color of the pixel PX may shift from the target color to anothercolor. The color shift is caused when light in the area of the subpixelSPB which has been transmitted from the array substrate AR side istransmitted through the color filter 21 which is opposed to the subpixelSPR, or when the opposite occurs. In the present embodiment, the metalline ML which is provided in each of the slits SL1 and SL2 functions asa light-blocking layer at the boundary of the subpixels SPR and SPB andprevents such a color shift.

Further, if the metal line ML in each of the slits SL1 and SL2 isuniformly arranged besides either one of the subpixel SPR or thesubpixel SPB, the color shift prevention effect will be produced ineither one of the subpixel SPR and the subpixel SPB. In this respect,according to the structure of FIG. 10, since the arrangement position ofthe metal line ML is changed from one slit to another slit, the impactof the color shift can be evenly spread to the subpixel SPR and thesubpixel SPB.

As described above, in the present embodiment, it is possible to improvethe display quality of the display device 1 by providing the second slitSL2 which overlaps the image signal line S in the common electrode CE,setting the pitch P of each of the slits SL1 and SL2 in theabove-described manner, and arranging the metal line ML in theabove-described manner. In addition to the above, various otheradvantages can be achieved from the present embodiment.

Second Embodiment

The second embodiment will be described. In the present embodiment,structural elements which are the same as or are similar to those of thefirst embodiment will be denoted by the same reference numbers. Further,unless otherwise specified, the present embodiment has the samestructure as that of the first embodiment.

FIG. 11 is a plan view schematically showing the structure of the secondembodiment. Here, a part of the first common electrode CE1 and a part ofthe second common electrode CE2 which are adjacent to each other via thefirst slit SL1 will be mainly described.

In the display area DA, a large number of first spacers SP1 and a largenumber of second spacers SP2 are provided. For example, the firstspacers SP1 are provided in the array substrate AR, and the secondspacers SP2 are provided in the countersubstrate CT. The spacers SP1 andSP2 contact each other between the array substrate AR and thecountersubstrate CT and form a cell gap between the first alignment film14 and the second alignment film 23.

The spacers SP1 and SP2 are formed, for example, in a position where thespacers SP1 and SP2 overlap the scanning signal line G, the image signalline S, and the light-blocking layer BM in planar view. In the exampleshown in FIG. 11, the first spacer SP1 is elongated in the seconddirection D2, and the second spacer SP2 is elongated in the firstdirection D1. According to this design, the spacers SP1 and SP2 can havea sufficient margin for contact. Therefore, even if the spacers SP1 andSP2 are inaccurately positioned due to manufacturing errors or thecountersubstrate CT and the array substrate AR are misaligned with eachother due to external force, the cell gap can be excellently maintained.

In the present embodiment, the first metal line ML1 near the first slitSL basically extends continuously along the first slit SL1 in the samemanner as that of the first embodiment. However, to prevent the firstmetal line ML1 from overlapping the first spacer SP1 in planar view, thefirst metal line ML1 is disconnected near the first spacer SP1. Further,each of the common electrodes CE1 and CE2 includes a recess RP near thefirst spacer SP1. Since the first spacer SP1 is formed in an area whichis surrounded by the recesses RP of the common electrodes CE1 and CE2,the first spacer SP1 will not overlap the common electrodes CE1 and CE2.

As in the present embodiment, when the first spacer SP1 does not overlapthe common electrodes CE1 and CE2 or the first metal line ML1, theheight of the first spacer SP1 can be accurately determined.

Note that, although the spacers SP1 and SP2 which overlap the first slitSL1 are mainly illustrated in FIG. 11, the same also applies to thestructure near the spacers SP1 and SP2 which overlap the second slitSL2. Further, the metal line ML which does not overlap the slits SL1 andSL2 is similarly disconnected in the position corresponding to the firstspacer SP1. In this case, to prevent the first spacer SP1 fromoverlapping the common electrode CE, the common electrode CE may beopened near the first spacer SP1.

Note that, although the cell gap is formed by the two spacers SP1 andSP2 in the present embodiment, a cell gap may also be formed by onespacer which extends from the array substrate AR or the countersubstrateCT. In this case also, a structure similar to that shown in FIG. 11 canbe adopted as the structure of the spacer.

Third Embodiment

The third embodiment will be described. In the present embodiment,structural elements which are the same as or are similar to those of thefirst embodiment will be denoted by the same reference numbers. Further,unless otherwise specified, the present embodiment has the samestructure as that of the first embodiment.

FIG. 12 is a plan view schematically showing an example of the layout ofthe metal lines ML and the common electrodes CE of the third embodiment.The example shown in FIG. 12 is different from the example shown in FIG.10 in that the metal lines ML are intermittently formed near the slitsSL1 and SL2.

In FIG. 12, a first metal line ML1 and a third metal line ML3 arearranged near the first slit SL1, and a second metal line ML2 and afourth metal line ML4 are arranged near the second slit SL2. Morespecifically, these metal lines ML1 to ML4 are continuously formed alongthe slits SL1 and SL2 between the adjacent scanning signal lines G.

The metal lines ML1 and ML3 partly cover the first slit SL1. Morespecifically, the first metal line ML1 is in contact with the edge ofthe third structural electrode SE3 and is spaced apart from the secondstructural electrode SE2. Further, the third metal line ML3 is incontact with the edge of the fifth structural electrode SE5 and isspaced apart from the sixth structural electrode SE6.

The metal lines ML2 and ML4 partly cover the second slit SL2. Morespecifically, the second metal line ML2 is in contact with the edge ofthe first structural electrode SE1 and is spaced apart from the secondstructural electrode SE2. Further, the fourth metal line ML4 is incontact with the edge of the fifth structural electrode SE5 and isspaced apart from the fourth structural electrode SE4.

In the example shown in FIG. 12, projections PR are formed at both endsof each of the metal lines ML1 to ML4. The projections PR of each of themetal lines ML1 to ML4 extend toward the structural electrode SE whichis in contact with each of the metal lines ML1 to ML4. Note that theprojection PR may be provided at one end of each of the metal lines ML1to ML4.

According to the above-described embodiment, in the slits SL1 and SL2,the metal lines ML provided closer to the subpixels SPR and the metallines ML provided closer to the subpixels SPB are alternately arrangedin the extension direction of the slits. Also in the first direction D1,the metal lines ML provided closer to the subpixels SPR and the metallines ML provided closer to the subpixels SPB are alternately arrangedin a manner similar to that of the example shown in FIG. 10. In thisway, the arrangement positions of the metal lines ML in the slits SL1and SL2 are evenly spread to the subpixels SPR and the subpixels SPB notonly in the first direction D1 but also in the extension direction ofthe slits SL1 and SL2, and the color shift and the impact of the streakwhich is associated with the leakage of the electric field can befurther suppressed.

Further, it is possible, by providing the projections PR, to ensureelectrical connection between the metal lines ML and the structuralelectrodes SE near the slits SL1 and SL2. In this way, it becomespossible to prevent such a situation where the metal line ML does notcontact the structural electrode SE due to manufacturing errors or thelike, that is, the metal line ML becomes floating.

In addition to the above, the present embodiment can also achieve thesame advantages as those achieved from the first embodiment.

Fourth Embodiment

The fourth embodiment will be described. In the present embodiment,structural elements which are the same as or are similar to those of thefirst embodiment will be denoted by the same reference numbers. Further,unless otherwise specified, the present embodiment has the samestructure as that of the first embodiment.

FIG. 13 is a plan view schematically showing the structure of the fourthembodiment. Here, a part of the first common electrode CE1 and a part ofthe second common electrode CE2 which are adjacent to each other via thefirst slit SL1 are mainly described. In the present embodiment, a shieldelectrode 30 is further added to the structure of the first embodiment.The shield electrode 30 is formed of a transparent conductive materialsuch as ITO. It is assumed that, although the shield electrode 30 has anarbitrary potential, for example, the shield electrode 30 has the samepotential as that of the common electrode CE, and the common voltage isapplied to the shield electrode 30.

The shield electrode 30 extends together with the first metal line ML1in the extension direction of the image signal line G. In the exampleshown in FIG. 13, the shield electrode 30 overlaps the entire first slitSL1. As another example, the shield electrode 30 may overlap a part ofthe first slit SL which is not covered with the first metal line ML1,and may not overlap a part of the first slit SL which is covered withthe first metal line ML1.

FIG. 14 is a sectional diagram taken along line XIV-XIV of FIG. 13. Inthe example shown in the drawing, the shield electrode 30 and the pixelelectrode PE are formed in the same layer, that is, between the thirdinsulating layer 13 and the first alignment film 14. The shieldelectrode 30 is opposed to the light-blocking layer BM.

Note that the shield electrode 30 and the pixel electrode PE may bearranged in different layers. For example, the third insulating layer 13may be separated into two layers, and the shield electrode 30 may bearranged between these layers. Although the structure near the firstslit SL1 is mainly described with reference to FIGS. 13 and 14, theshield electrode 30 is also arranged in the second slit SL2 in the samemanner.

As the shield electrode 30 is arranged according to the presentembodiment, in the slits SL1 and SL2, the leakage of the electric fieldwhich is not completely prevented by the metal line ML can be preventedby the shield electrode 30. Therefore, the display quality of thedisplay device 1 can be further improved.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

For example, the structure of the above-described embodiments can beappropriately combined with each other.

Further, the display device 1 which has a touch detection function hasbeen described in the embodiments. However, the technical ideasdisclosed in the embodiments are also applicable to a display devicewhich does not have a touch detection function.

Still further, each of the slits SL1 and SL2 is arranged between thesubpixels SPR and SPB in the embodiments. However, each of the slits SL1and SL2 may also be arranged between the subpixels SPR and SPG orbetween the subpixels SPG and SPB.

Still further, the common electrodes CE in the embodiments may also bephysically separated from each other on a structural electrode SE basis.In this case, as the structural electrodes SE are electrically connectedto each other by the metal lines ML, one common electrode CE can beformed.

What is claimed is:
 1. A liquid crystal display device comprising: aplurality of image signal lines; a plurality of scanning signal linescrossing the plurality of image signal lines; a plurality of pixels; adisplay area including the plurality of pixels; a plurality of pixelelectrodes which are respectively provided in the plurality of pixels;and a plurality of common electrodes which are respectively opposed tothe plurality of pixel electrodes, wherein the plurality of commonelectrodes are configured to detect an object which is in contact withor in proximity to the display area and to display an image in thedisplay area, the plurality of common electrodes include a first commonelectrode and a second common electrode which are arranged in a firstdirection in which one of the plurality of scanning signal linesextends, a first slit is provided between the first common electrode andthe second common electrode, the first common electrode and the secondcommon electrode are supplied a signal different from each other, asecond slit is provided in the first common electrode, and each of thefirst slit and the second slit overlaps one of the image signal linesand extends in an extension direction in which the image signal lineextends.
 2. The display device of claim 1, wherein the first commonelectrode includes in the extension direction, a first area, a secondarea adjacent to the first area, and a third area adjacent to the secondarea, and the second slit is provided in the second area and is notprovided in at least one of the first area and the third area.
 3. Thedisplay device of claim 2, further comprising: a surrounding arealocated outside the display area; and a light-blocking layer whichoverlaps the surrounding area, wherein the first area and the third areaare located in the surrounding area and overlap the light-blockinglayer.
 4. The display device of claim 1, wherein the pixel includes nsubpixels, the plurality of second slits which are arranged in the firstdirection are provided in the first common electrode, the number of thesubpixels which are arranged in the first direction between the adjacentsecond slits is an integral multiple of n.
 5. The display device ofclaim 1, wherein the plurality of second slits which are arranged in thefirst direction are provided in the first common electrode, the numberof the pixels which are arranged between the first slit and the secondslit and between the adjacent second slits is m, the number of thepixels which overlap the first common electrode in the first directionis q, and q is an integral multiple of m.
 6. The display device of claim1, wherein in the first direction, the number of the pixels whichoverlap with the first common electrode differs from the number of thepixels which overlap with the second common electrode.
 7. The displaydevice of claim 1, further comprising a plurality of metal lines whichoverlap the image signal lines, extend in the extension direction, andcontact the common electrodes, wherein the plurality of metal linesinclude a first metal line and a second metal line, and the first metalline partly covers the first slit, and the second metal line partlycovers the second slit.
 8. The display device of claim 7, wherein thefirst common electrode includes a first structural electrode and asecond structural electrode, the second common electrode includes athird structural electrode, the first structural electrode and thesecond structural electrode are adjacent to each other via the secondslit, the second structural electrode and the third structural electrodeare adjacent to each other via the first slit, the first metal line isin contact with the third structural electrode and is spaced apart fromthe second structural electrode, and the second metal line is in contactwith the first structural electrode and is spaced apart from the secondstructural electrode.
 9. The display device of claim 8, wherein theplurality of metal lines further include a third metal line and a fourthmetal line, the first common electrode further includes a fourthstructural electrode and a fifth structural electrode, the second commonelectrode further includes a sixth structural electrode, the firststructural electrode and the fourth structural electrode, the secondstructural electrode and the fifth structural electrode, and the thirdstructural electrode and the sixth structural electrode are adjacent toeach other, respectively, in the extension direction, the fourthstructural electrode and the fifth structural electrode are adjacent toeach other via the second slit, the fifth structural electrode and thesixth structural electrode are adjacent to each other via the firstslit, the third metal line is in contact with the fifth structuralelectrode and is spaced apart from the sixth structural electrode, thefourth metal line is in contact with the fifth structural electrode andis spaced apart from the fourth structural electrode.
 10. The displaydevice of claim 7, further comprising: a first substrate; a secondsubstrate; and a liquid crystal layer provided between the firstsubstrate and the second substrate, wherein the first substrate includesa first spacer provided between the first common electrode and thesecond common electrode, the second substrate includes a second spacerwhich is provided between the first common electrode and the secondcommon electrode and is in contact with the first spacer, the firstspacer and the second spacer overlap the image signal line and thescanning signal line in planar view, and the first metal line overlapsneither the first spacer nor the second spacer in planar view.
 11. Thedisplay device of claim 10, wherein each of the first common electrodeand the second common electrode includes a recess in planar view, andthe first spacer and the second spacer are located in an area which issurrounded by the recess of the first common electrode and the recess ofthe second common electrode in planar view.
 12. The display device ofclaim 1, further comprising a shield electrode which extends in theextension direction of the image signal line and to which apredetermined voltage is applied, wherein the shield electrode overlapseither the first slit or the second slit in planar view.
 13. The displaydevice of claim 1, wherein the distance between the first slit and thesecond slit is less than or equal to 180 μm.
 14. The display device ofclaim 13, wherein the distance between the first slit and the secondslit is less than or equal to 150 μm.
 15. The display device of claim13, wherein the distance between the first slit and the second slit isgreater than or equal to 80 μm.
 16. The display device of claim 15,wherein the distance between the first slit and the second slit isgreater than or equal to 100 μm.
 17. The display device of claim 1,wherein the plurality of second slits arranged in the first directionare provided in the first common electrode, and the distance between theadjacent second slits is less than or equal to 180 μm.
 18. The displaydevice of claim 17, wherein the distance between the adjacent secondslits is less than or equal to 150 μm.
 19. The display device of claim17, wherein the distance between the adjacent second slits is greaterthan or equal to 80 μm.
 20. The display device of claim 19, wherein thedistance between the adjacent second slits is greater than or equal to100 μm.